Hydraulic well pumping system



June 30; 1970` cs. K. Roi-:DER l3,517,74T

HYDRAULIC WELL PUMPING SYSTEM Filed Jim@ 5, 1968 3 Sheets-Sheet 1 FIG. la

Ill n d @J m, Il l" fili-' June 30, 1970 G. K. ROEDER HYDRAULIC WELL PUMPING SYSTEM 3 Sheets-Sheet 2 Filed June 5, 1968 G. K. ROEDER HYDRAULIC WELL PUMPING SYSTEM June 30, 1970 3 Sheets-Sheet 3 Filed June 5, 1968 United States Patent O ABSTRACT OF THE DISCLOSURE Apparatus for operating a down hole hydraulic well pumping system. One aspect of the invention is directed to a method for injecting spent power iluid into a lower or upper stratum of the ground While extracting energy from the power fluid in order to pump oil from another stratum to the surface of the ground. The apparatus comprehends a new combination of a production unit having a piston and control valve assembly which forms an engine for actuating a down hole pump. The piston and control valve assembly cooperates with the down hole pump motor in a manner to enable spent power lluid from the engine to be injected through a standing valve assembly and into a stratum located below or above the producing formation.

BACKGROUND OF THE INVENTION Various fluid operated deep Well pumps, sometimes called hydraulic oil well pumping or production units, are known to those skilled in the art. These production units generally include a valve system which receives power iluid from a pump located above the surface of the ground and which controllably supplies the power lluid to an engine. The engine reciprocates a piston rod which in turn actuates a lluid pump. The spent power fluid is generally commingled with the production lluid and forced to the surface of the ground by the action of the pump. Various prior art control valve and enginev assemblies have proven successful for use in deep Wells.

In the production of oil and other iluids from deep wells having multiple producing formations, it may be desirable to dispose of either fresh or salt water which is sometimes produced along with oil. The disposal of this salt water is often costly. IOn the other hand, in water llooding programs and the like, it may be necessary to provide a source of water in order to flood various oil producing stratum with a low cost disposable fluid. Under these circumstances it may be necessary to purchase the Water since its use in a controlled program results in an economic gain in the form of increased production. An advantageous expedient recognized by the oil industry is the injection of gases, steam, salt or fresh water, as well as other treating chemicals in order to produce various oil strata.

SUMMARY OF THE INVENTION The present invention comprehends both a method and apparatus for transferring spent power iluid from a production formation into a Water llood zone. The spent power fluid includes oil or water which is eliminated from a down hole pump in producing oil from an oil production stratum. The water llood zone or stratum may be located either above or below the production formation. In exemplifying the present invention, a standing valve assembly is used in conjunction with other apparatus as an illustration. The valve is placed in communication with a production formation with the valve assembly being separated from the water flood zone and the production formation -by means of a packer. The valve cooperates with a hydraulic oil well production unit and includes telescopingly arranged parts having passageways 3,517,741v Patented June 30, 1970 Cce therein which normally permit the llow of produced oil through the valve and into the pump of the production unit where the pump lifts the produced oil to the surface of the earth. Simultaneously, the valve permits the spent power fluid from the engine to ilow into a Water llood zone, thereby precluding commingling of the spent power fluid With the produced oil as well as preventing commingling of the water ilood zone with the production zone. The valve is selectively shifted to a shut off nonproducing position in order to enable removal of the bottom hole production unit while precluding commingling of the two formations. In this latter position, the telescoping coacting parts of the standing valve assembly precludes the flow of fluid between the production formation and the water flood zone to thereby enable replacement of the bottom hole pump as well as to make possible the chemical treatment of either zone and to permit bottom hole pressure testing of either zone to be carried out separately from one another.

The present invention further comprehends a specific hydraulic oil well pumping system which enables the practice of the above method. The pumping system includes the before mentioned standing valve in combination with a production unit having a piston and control valve which unitizes the valve assembly and motor into a single reciprocating piston and control valve arrangement. The piston and control valve which forms the engine and valve assembly includes a hollow connecting rod reciprocatingly attached to the piston of a conventional double acting oil production pump. The hollow rod continues from the engine, through the pump, and into lluid communication with the standing valve by means of an isolation tube and stinger pipe. Production lluid from the standing valve ilows about an annulus formed between the stinger tube and the standing valve and into the pump unit, while the spent power fluid llows through the stinger tube and through a series of passageways provided within the standing valve to Where it is ultimately dissipated into a water flood zone, or the like.

A still further object of the present invention is the provision of apparatus for utilizing spent power fluid from a down hole production unit in order to treat another production zone.

A further object of the present invention is to provide an engine for a double acting bottom hole pump which utilizes a combination piston and control valve arrangement.

Still another object of the present invention is to provide a novel hydraulic pumping system which includes the combination of a piston and control valve, a' bottom hole pump, and a standing valve.

A further object of the present invention is the provision of a standing valve which can be utilized with a xed insert, fixed casing, free parallel, or free casing pump system.

Another object of the present invention is the provision of an improved bottom hole pumping system which includes a production unit comprised of the combination which includes a piston and control valve integrated into a single moving unit, and which provides an engine which reciprocates a pump, with the spent power fluid from the engine being controllably llowed into a disposal zone of the Well by means of an improved standing valve assembly.

These and other objects of the present invention will become apparent to those skilled in the art after having digested the remainder of the present disclosure.

The above objects are attained in accordance with the present invention by the provision of a down hole pump assembly which is fabricated and used essentially as set forth in the above abstract.

3 BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B are fragmentary vertical cross-sectional views illustrating the hydraulic well pumping system of the present invention;

FIG. 2 is an enlarged vertical cross-sectional view showing a portion of the device seen in FIGS. lA and 1B;

FIG. 3 is a fragmentary vertical cross-sectional view of part of the device seen in FIG. 2, but shown in a different operating position;

FIG. 4 is an enlarged fragmentary cross-sectional view of part of the device seen in the foregoing figures;

FIG. 5 is a cross-sectional view taken along line 5 5 of FIG. 2; and

FIG. 6 is a cross-sectional view taken along line 6 6 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Looking now to the details of the drawing, and in particular to FIGS. 1A and 1B, in conjunction with the remaining figures, there is seen an oil producing stratum 6, a water ood zone 7, a vertical bore hole having a casing 8 coextensive therewith, and with a packer 9 separating the two strata from one another. The packer is attached to a foot 10 having power tubing 11 upwardly depending therefrom and with the hydraulic well pumping system being operatively connected to the piping and to the foot. Slidably located within the power tubing there is seen a portion of the hydraulic well pumping system which includes a production unit having an apertured nose 12 about which there are sealingly positioned spaced apart packers 14 located on the power fluid inlet 16. The inlet diverges into a circumferentially extending packer seal assembly 18 which is provided with a circumferentially extending groove having an O-ring 20 sealingly located therein. The O-ring is slidably received in close tolerance fitting relationship within an O-ring collar 22. The packer seal assembly is connected to a stroke chamber sub 24 which in turn is threadedly attached to a barrel, generally indicated by the numeral at 25. The stroke chamber sub forms a chamber 26 within which the terminal end of an input rod 28 reciprocates. The stroke chamber reduces in diameter into an input rod passagesway 30 which includes a packing gland received within a counterbore 32 at the lower extremity thereof. The input rod is provided with a longitudinally extending hollow passageway 34 therethrough and is connected by inlet boss 36 to a novel piston and control valve arrangement generally illustrated by the arrow at numeral 40. The piston and control valve reciprocates within a cylinder formed internally of the barrel. The piston includes expansible metal sealing rings 38, 38 disposed at the upper and lower extremities thereof. The details of the piston and control valve will be discussed more fully later on.

From the piston a connecting rod extends downwardly from an outlet boss 41 in a manner as best seen at 42. The connecting rod interconnects the piston with a double acting pump 44. The details of the double acting pump are not set forth in detail, but generally the pump includes upstroke exhaust ports 45 and downstroke exhaust ports 46. Further details of the pump are not deemed necessary for a full comprehension of the invention since the design and construction of several such pumps are well known to those skilled in the art.

A hollow discharge rod extends from the lower extremity of the pump at 47 where it is slidably received in a reciprocative manner within an isolation tube 48 with the free end of the rod terminating therein. The pump inlet is in communication with the chamber formed between the outer peripheral wall surface of the isolation tube and the inside peripheral wall surface of the barrel.

A bottom plug 50 is threadedly attached to the lower end of the barrel and includes a multiplicity of longitudinally extending radially spaced apart drilled passageways 51. An isolation tube counterbore S4 sealingly receives the lower depending free end of the isolation tube in close fitting relationship therewith. About the isolation tube there is circumferentially disposed a groove having O-ring 52 fitted therein. The bottom plug includes a shoulder 56 which sealingly cooperates with the pump seat 56. The isolation tube counterbore reduces in diameter and continues as the lowermost portion of the hydraulic pump unit, also called a stinger, as seen at numeral 60. The outside peripheral wall surface of the depending marginal end portion of the stinger is provided with O-ring seals 61 which are slidably received within the illustrated shoulder of the counterbore.

A standing valve assembly, generally indicated by the numeral 62 is slidably received within counterbore 64 of the foot and includes the before mentioned pump seat. The standing valve further includes a telescoped member 83 which is made integrally with and downwardly depending from the before mentioned pump seat, and which is telescopingly received within a main body member 70 thereby leaving an annular area 66 between the main body member and the foot. The main body member is comprised of a lower portion 68 which is screw-threaded onto an upper portion 74 by means of threads 72. The two spaced apart enlargements Iare seen to be formed by members 74, 76 which cooperate to provide an annulus 78 therebetween. Enlargement 74 seats against the foot as seen at 80 while enlargement 76 is provided with seal means in the form of a circumferentially extending groove having an O-ring 82 therein. Pump seat 57 is provided with a lower hollow terminal end which is screw-threaded at 84 into engagement with a similarly threaded plug 86. The lower extremity of the plug includes biasing means 88 which biases the telescoped pump seat member in an upward direction. Cavity ow passageway 90 communicates with ports 92, and 93 and with chamber 94; while port 96 located within the foot communicates with annulus 78, ports 97, 98, 51, and annulus 100 when the valve is in the operative position. Port 99 is flow connected to port 99 which ow communicates the stinger with the lower formation by means of counterbore 64.

Cavity iiow passageway 90 also communicates with passageway 101 which is ow connected to the production tubing 102 and which carries production fluid from formation 6 to the surface of the ground.

Looking more particularly to the details of the integrated or unitized piston and control valve 40 (which is shown in greater detail in FIGS. 2 and 3) there is seen the before mentioned hollow input rod 28 and upper boss 36 at the uppermost portion of the figures. The boss has a shoulder near numeral 104 which abuts the uppermost face of the piston 40. fO-rings 106 seal the downwardly projecting portion of the boss which is received within counterbore 108 of the uppermost portion 110 of the piston. The threaded connection 112 rigidly aflixes the boss to the cylinder. The lowermost end of the boss forms a valve seat 114 at the lower extremity of the passageway 116. Radially extending passageways 118 provide fluid flow into drilled passageway 120.

The longitudinally extending drilled passageways 122 connect the chamber formed within the barrel above the piston to radial passageways 124. Second radial passageways 126 flow connect to the longitudinally extending passageways 128 by means of the chamber formed within the small cylinder 130. Piston 132 has a lower portion in the form of a Maltese Cross having radiating guides or `fins 134 thereon which are slidably received in close titting relationship within the small cylinder 130. The head 136 of the small piston seats against valve seat member 114. The lower extremity of the Maltese Cross at 138 freely abuts against the uppermost face of intermediate piston 140. Piston 140 includes an upper portion 142, lower portion 144, connected together by a reduced diameter portion which leaves an annulus y146 therewith. Piston 132 and 140 could be made into a single member,

however this particular construction is preferred since many alignment problems are eliminated by the illustrated construction.

Intermediate piston 140 reciprocates within intermediate cylinder 148 while the upper or small piston 132 reciprocates within the small cylinder 130, with each piston coacting together in a reciprocating manner as a single unit. Radial passageway 150 is fluid connected to outlet 151 by means of longitudinal passageway 152. Lower boss 154 is threadedly attached at 154 to the main body of the piston. Radial ports 158 and 160 are provided in the boss. A counterbore receives the lower boss in a manner similar to the upper boss 36. A drilled passageway 162 extends longitudinally through the piston and reciprocatingly receives pilot valve 164 therein. The pilot valve includes upper reduced terminal end 166, enlarged upper portion 168, spiral undercut 170, reduced diameter portion 172, lower enlarged portion 173, reduced diameter portion 174, and lower terminal end 167. As seen at 166, one terminal end of the pilot valve always protrudes from the piston and alternately engages or impacts against the packing gland 32 (FIG. l) or the packing gland of the motor (not shown).

OPERATION In operation the engine (i.e., the combustion piston and valve means) and pump are assembled into the illustrated production unit which is used in a system of the parallel free type. The production unit can also be used in a multiplicity of other systems. The entire production unit can be circulated into and out of the piping 11 by controlling the direction of flow through the piping and the production return line 102. With the flow of power fluid being in a downward direction through the piping 11, and the production unit assembled into a unitary apparatus with the unit being placed within the piping in the illustrated manner of FIG. 1A and 1B, the bottom plug seats within the pump seat 57 of the standing valve, with mutual contact being attained therebetween at 56. -Power luid ows down through the piping and into the apertured nose, through the packer seal assembly, and into the stroke chamber. The O-ring collar prevents power fluid from owing externally between the unit and the piping. The ow must therefore continue through the uppermost portion of the reciprocating hollow input rod 28 and into the piston and control valve assembly, where the power fluid reciprocatingly actuates piston 40 within the polished portion of the barrel.

In the operation of the combination piston and control valve, and as particularly seen in FIG. 2, the power fluid enters upper boss 36 where the main flow continues through radial passageway 118, longitudinal passageway 120, into the annulus 146, and through outlet 151 where the power iluid exerts a force upon the bottom of the piston to thereby force the piston in an upward direction within the 'barrel 25. Upper and lower rings 38 and 3S' prevent escape of uid between the piston and barrel. Flow of Huid through passageway 178, about the annulus formed by the reduced diameter portion of the pilot valve at 172, and into the area below piston portion 144 exerts an upward pressure upon the piston 140. Noting the difference in area of intermediate piston at 144 and small piston at 136, it is seen that the area of piston 144 with respect to piston 136 is unequal and accordingly the small piston 132 is maintained forceably seated against valve seat 114. The contoured valve portion 136 of the small piston together with the cooperative action between small cylinder 130 and the upper cylindrical portion of the piston prevents escape of uid therethrough. This cooperative action between the recited elements provides a double seal.

As the piston 40 travels in an upward direction in order to assume the illustrated position of FIG. 2, the fluid within chamber 33 must escape to allow movement of the piston into the upper portion of the cylinder as the piston travels toward packing gland 32. This is accomplished by the provision of passageways 122 which are interconnected to passageways 128 by means of radial passageways 124, 126, and to the'free portion of cylinder 130 (i.e.: between the elements or -fns of the Maltese Cross) in order to permit the ilow of uid through radial passageway 160 and through the hollow connecting rod 42. As the piston travels in this manner in an upward direction, it reaches its limit of travel (FIG. 2) whereupon the upper terminal end of the pilot valve at 166 contacts the packing gland 32 to thereby drive the pilot valve in a downward direction to the position illustrated in FIG. 3.

Looking now to the details of FIG. 3 in conjunction with FIGS. l and 2, in order to explain the action of the engine valve system on the downstroke, those skilled in the art will now realize that power iluid from the hollow passageway 34 flows against small piston 132 thereby driving it in a downward direction along with the intermediate piston within the cylinder 148 until the lowermost portion 144 of the piston abuts member 154. This action bring the device into the configura/tion of FIG. 3 and permits the tlow of iluid to occur through passageway 124, 122, whereupon the iluid pressure is exerted against the upper face of the piston thereby driving the main pistion 40 in a downward direction where the piston assumes the piston of FIG. 3. Fluid located below the main piston and above the seal pack-olf liner (not shown but located in the area generally indicated by numeral 142) must exhaust therefrom in order to enable the piston to travel downwardly within the barrel. This is accomplished by the provision of passageway 152 which permits fluid ow into the cylinder 130, through radial passageway 126, longitudinal passageway 128, radial passageway 160, and through the hollow connecting rod 42, where the fluid ultimately reaches the isolation tube. The combination piston and control valve, or engine, continues to reciprocate in this manner so long as a power source is supplied to the engine and valve assembly, and so long as the outlet 42 is at a sufficiently reduced pressure with respect to the uid in passageway 34.

`Connecting rod 42 reciprocatingly actuates the double acting pump 44 with the pump inlet being in communication with the annulus provided between the isolation tube 48 and the barrel. Pump outlets 45 and 46 deliver uid in a downward direction into annulus 90, up through passageway 101, and into the production tubing 102 where the Huid is forced to ground level. The spent power lluid from hollow -connecting rod 42 flows through central passageways located in the pump where it exits at the depending terminal end of the hollow discharge rod as seen at 47 in FIG. 1B. Since the isolation tube 48 is sealed within counterbore 54 of the bottom plug 50 the iluid must continue to flow through the lower hollow depending end of the plug and through the stinger as seen at 58, whereupon the fluid then flows through radial passageways 99 and 99', into the annulus between the main body member and the foot at 66, to where the spent power fluid then flows through the perforations 7 below the packer 9 and into the water flood zone 7.

Still looking to the details of FIGS. 1A and 1B it will now be realized that production fluid from formation 6 flows into the perforations 6 to provide a production fluid level 141 within the casing 8. The production iluid enters the foot through radial passageway 96 where the uid iiows through annulus 78, through radial ports 97, 98 and into the annulus about the lower depending end of the stinger where the uid is then free to flow upwardly through the spaced apart radial production fluid inlet passageways 51 and into the barrel of the pump.

When it is desired to retrieve the production unit, the power fluid flow is discontinued and circulation is reversed by applying a positive pressure upon the production return line. This action simultaneously forces the production unit and the pump seat of the free standing valve in an upward direction whereupon the unit is then forced from the pump seat and to the ground level as fluid is pumped through the production return line. It will be noted that the pump seat follows the pump for a limited distance when lluid pressure is exerted through radial passageway 92, longitudinal passageway 93, and into the chamber 94. This action is due to the difference in area of the pump which is exposed to the uid pressure from productine line 102, which forces telescoping member 57 to move upward with respect to the main body member 74 thereby misaligning ports 97 with respect to ports 98- and misaligning ports 99 with respect to ports 99'. Spring 88 assures the continued misalignment of the ports to thereby preclude comingling of liquid from the water ood zone 7 with uid from the production zone 6. When the production unit is pumped back into operative position, the lowermost depending end portion, or stinger, of the plug again enters the pump seat thereby forcing the standing valve back into the open position of FIG. 1B.

The free standing valve of the present invention also permits either or both zones 6 and/or 7 to be simultaneously treated with various chemicals while using an isolation tool and while the production unit is removed from the piping. This operation is best carried out by positioning an isolation tool onto the standing valve in order to expose the zone to be treated while blocking off the remaining zone. When the treatment has been accomplished, the isolation tool is pumped out of the hole. As the tool is pumped from the hole, the standing valve will shift to the closed position prior to the tool leaving the valve seat, in accordance with the previously described operation of the valve in conjunction with the pump.

It is contemplated to use the present invention in combination with various operations other than oil production. In sulphur production, for example, superheated water can be used as the power fluid with the spent power liuid being injected below the molten sulfur in order to place additional sulfur into solution. Accordingly, the use of water as the power fluid in order to produce oil from an oil bearing formation should be considered as one of many exemplilications of the present invention.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modications and equivalents may be resorted to, falling within the scope of the invention as claimed.

I claim:

1. A down hole production unit for pumping fluid from a liuid producing zone to the ground level;

said production unit including engine means, pump means, power fluid inlet means, spent power iuid outlet means, production fluid inlet means, and production fluid outlet means;

means connecting said engine means to saidy power fluid inlet means, said engine means being connected to said pump means by a hollow connecting rod, which is ow connected to said spent power huid outlet means, a hollow discharge rod depending away from said pump means and having means by which it is ow connected to said hollow conecting rod; an isolation tube, said hollow discharge rod being received by said isolation tube in sealed relationship therewith, said hollow discharge rod adapted to move with respect to said isolation tube; means flow connecting said isolation tube to another zone isolated from the lluid producing Zone said production fluid inlet means adapted to connect said pump means for conducting fluid flow to the ground level;

said production fluid inlet means adapted to connect said pump means to a liuid producing zone; whereby: power fluid can actuate said engine means which in f5 turn actuates said pump means to thereby allow production fluid to flow to the surface of the ground while spent power fluid is maintained separated from said production uid.

2. The production unit of claim 1 and further including a bottom plug positioned below said pump means, said spent power fluid outlet means including a spent fluid flow passageway through said bottom plug; said isolation tube being flow connected to said spent fluid llow passageway of said bottom plug; said production fluid inlet means including a flow passageway formed through a portion of said bottom plug; whereby:

production uid can flow from one fluid producing formation, through said bottom plug, and to said pump while spent power fluid can flow from said isolation tube through said bottom plug and to another formation with the production and spent power fluid liow paths being maintained separate from each other.

3. The production unit of claim 2 wherein said bottom plug further includes a hollow downwardly depending free end portion which forms a stinger, said spent power uid flow passageway through said bottom plug including said hollow stinger; whereby;

said stinger isolates the spent power fluid from the production uid.

4. The production unit of claim 1, and further including a bottom plug underlying said pump means, said plug having means forming a seat from which there downwardly depends a hollow portion in the form of a stinger, said isolation tube being iiow connected to the hollow stinger;

said bottom plug further including 4a production fluid ow passageway therethrough which forms said production fluid inlet means;

a standing valve underlying said pump means and adapted to be positioned within a bore hole; said standing valve having a main body member and a pump seat member with said pump seat member being slidably received within said main body member and adapted to be moved from a producing to a shut-in position; said pump seat member and said main body member having means forming a spent power uid ow passageway therethrough and a production fluid flow passageway therethrough with fluid ow occurring through the last two recited fluid flow passageways when the pump seat member is in the producing position; and

said pump seat member having means forming a seat therein which sealingly engages the plug seat in a manner to maintain said production fluid isolated from said spent power liuid.

5. The production unit of claim 1, and further including a standing valve underlying said pump; said standing valve including a main body member and a pump seat member, said pump seat member having means forming a seat which is adapted to cooperate with said production iiuid inlet means and said spent power fluid outlet means; said pump seat member having a portion thereof slidably received by said main body member with said pump seat member being movable from a producing to a shutin position;

means forming a spent power fluid ow passageway through said main body and adapted to be placed in ow communication with a portion of a borehole, means forming a spent power fluid passageway through said pump seat member which is aligned with said passageway through said main body when the standing valve is in the producing configuration and which is misaligned therewith when the standing valve is in the shut-in configuration;

the lower marginal end portion of said pump adapted to be received by said pump seat member to thereby urge said pump seat member into the production configuration to enable production fluid to flow from another portion of the -borehole to said pump while spent power fluid ows to the first recited portion of the borehole.

6. The production unit of claim 1, wherein said engine means including a barrel, a main piston reciprocatingly received within said barrel, means forming a stroke chamber, said hollow connecting rod depending from said piston and further including means by which it is sealingly and reciprocatingly received within said stroke chamber, said stroke chamber being flow connected to and forming part of said power iluid inlet means; said hollow connecting rod interconnecting said main piston to said pump for imparting reciprocatory motion to said pump while conducting spent power fluid from the engine, and means including said barrel forming an upper fluid chamber above and a lower iluid chamber below said main piston;

means forming a first cylinder chamber and a reduced diameter cylinder chamber within said main piston; large and small pistons, respectively, reciprocatingly received within said first and said reduced diameter cylinder chambers, respectively; said large piston having means associated therewith for controlling flow through said first cylinder chamber, said small piston having means associated therewith for controlling flow through said reduced diameter cylinder chamber;

a pilot valve means longitudinally extending through said main piston and adapted to shift from one to another flow position in response to the position of the main piston;

means forming a first flow passageway from said upper chamber, to said reduced diameter chamber and into communication with said hollow connecting rod; means forming a power fluid passageway from said input rod to said reduced diameter chamber;

means forming a second flow passageway from said lower cham-ber into said first cylinder chamber and into said input rod;

means forming a passageway from the lower extremity of said lirst cylindrical chamber into communication with said input rod; whereby:

said pilot valve means, when in said one position permits flow to occur from said input rod to the lower extremity of said first cylindrical chamber to cause said large and small pistons to move upwardly thereby allowing fluid flow to continue to the lower chamber to force the main piston in an upward direction while simultaneously flow occurs fromsaid upper chamber to said hollow connecting rod.

7. In a hydraulic fluid actuated down hole production unit for pumping uid from a fluid producing zone in a borehole to the surface of the ground while simultaneously treating a second zone located within the borehole with spent power uid, in combination: a pump and engine assembly removably received within the borehole;

power fluid inlet means for actuating said engine with power fluid, production fluid inlet and outlet means for said pump, spent power iluid outlet means for said engine, means connecting said pump and engine assembly together to enable the engine to actuate the pump, a bottom plug underlying said pumps and having means forming a seat thereon and a spent power fluid passageway therein for the flow of spent power fluid therethrough, and further including means forming a production iluid passageway through said bottom plug for flow of production fluid therethrough;

a standing valve adapted to be attached within a borehole in underlying relationship to said pump and engine assembly, and including a main body member and a pump seat member, said pump seat member having means forming a seat thereon which can sealingly engage the seat of said bottom plug; said main body member having means by which said pump seat member can be slidably received by said main body member to enable said pump seat member to be moved from a producing to a shut-in position with respect to said main body member;

means forming a spent power fluid flow passageway and a production fluid flow passageway, respectively, through said main body member so as to enable fluid communication to be established with a second zone and with a fluid producing zone, respectively; means forming a spent power fluid passageway and a production iluid flow passageway, respectively, through said pump seat member which can be aligned with said spent power fluid lloW passageway and said production fluid flow passageway, respectively, of said main body member when the standing valve is in the producing configuration and which is misaligned therewith when the standing valve is in the shut-in configuration;

the seat on said bottom plug adapted to be received by said pump seat member to thereby urge said pump seat member into the production configuration to enable production fluid to flow to said pump while spent power fluid flows to the recited second zone.

8. The downhole production unit of claim 7 wherein said engine and pump assembly includes a barrel, a main -piston having a control valve assembly therein reciprocatingly received within said barrel, means forming a stroke chamber, a hollow input rod upwardly depending from said piston and sealingly and slidably received within said stroke chamber, said stroke chamber adapted to be flow connected to said power iluid inlet means; a hollow connecting rod connecting said main piston to said pump for imparting reciprocatory motion to said pump while conducting spent power fluid from the engine, and means including said main piston and said barrel forming a fluid chamber above and a fluid chamber below said main piston;

means forming a first cylinder chamber and a reduced diameter cylinder chamber within said main piston; large and small pistons, respectively, reciprocatingly received within said lirst and second reduced diameter cylinders chambers, respectively; said large piston having a reduced diameter mid-portion, said small piston having a reduced cross-sectional area along its lower marginal end portion;

a pilot valve means longitudinally extending through said main piston and adapted to be actuated by movement of said main piston;

means forming a first flow passageway from said upper chamber to said reduced diameter chamber and into communication with said hollow connecting rod;

means forming a passageway from said lower chamber into said first cylinder chamber, and into said input rod;

means forming a passageway from the lower extremity of said first cylindrical chamber into communication with said passageway from said lower chamber; said pilot valve means controlling fluid flow through said passageway from the lower extremity of said first cylindrical chamber to the reduced diameter midportion of said large piston and to said hollow connecting rod; whereby:

power iluid is alternately flow connected to said upper and lower chamber while spent power fluid is alternately connected to flow from said upper and lower chamber to said hollow connecting rod.

9. An engine for actuating a double acting down hole pump assembly comprising a barrel, a main piston having means forming a control valve assembly therein for causing reciprocation of said main piston with power fluid, said main piston reciprocatingly received within said barrel, means forming a stroke chamber, a hollow input rod upwardly depending from said piston and sealingly and reciprocatingly received within said stroke chamber, said stroke chamber adapted to be flow connected to a source of power uid; a hollow connecting rod interconnecting said engine to the pump for imparting reciprocatory motion into the -pump while conducting spent power iuid from the engine, said means including said barrel forming a uid chamber above and below `Said main piston;

said means forming a control valve assembly includes a rst cylinder chamber and a reduced diameter cylinder chamber; large and small pistons, respectively, reciprocatingly received within said first and reduced diameter cylinder chambers, respectively;

a pilot valve means longitudinally extending through said main piston and adapted to shift from one t another iiow controlling position in response to the position of the main piston in said barrel;

means forming a first ow passageway from said upper fluid chamber, to said reduced diameter chamber and from the last named chamber into communication with said hollow connecting rod; means forming a power fluid passageway from said input rod to said reduced diameter chamber;

means forming a second ow passageway from said lower fluid chamber into said first cylinder chamber and from said first cylinder chamber into said input rod;

means forming a passageway from the lower extremity of said first cylindrical chamber into communication with said input rod;

said pilot valve means, when in said one position permits ow to occur from said input rod to the lower extremity of said rst cylindrical chamber to cause said large and small pistons to move upwardly thereby allowing power uid ow to continue to the lower uid chamber to force the main piston in an upward direction while simultaneously ow occurs from said upper uid chamber to said hollow connecting rod;

said pilot valve means, upon being shifted to the recited another position, permits flow to occur from said input rod to the upper extremity of said reduced diameter chamber, causing said large and small pistons to move downwardly, thereby allowing power fluid to flow to the upper fluid chamber to force the main piston in a downward direction while simultaneously ow occurs from said lower fiuid chamber to said hollow connecting rod.

10. The engine of claim 9 wherein said down hole pump assembly includes a double acting pump, means forming a longitudinal passageway through said pump; said hollow connecting rod flow connected to the last said passageway; a downwardly depending outlet tube flow connected to the last named passageway; an isolation tube which sealingly and reciprocatingly receives said outlet tube;

a bottom plug attached to said pump and having means forming a production fluid passageway therein with the last named passageway being in ow communication with said pump, means forming a hollow stinger which downwardly depends from said plug, said isolation tube being iiow connected to said hollow stinger; whereby:

spent power fluid ows through said stinger while production fluid ows along a separate path and through said bottom plug.

11. The engine of claim 9 and further including a bottom plug, means forming a spent uid flow passageway through said bottom plug; an isolation tube being ow connected to said spent uid ow passageway of said bottom plug; means forming a production uid ow passageway through said bottom plug with the last said flow passageway forming said production fluid inlet means; whereby:

production Huid flows through said bottom plug to said pump while spent power fluid flows from Said isolation tube through said bottom plug with the production and spent power uid flow paths being maintained separate from each other.

12. The apparatus defined in claim 11, and further including a standing valve, said standing valve including a main body member and a pump seat member, said pump seat member having means forming a seat which cooperates with said production fluid and said spent power fluid passageways; said pump seat member having a portion thereof slidably received by said main body member with said pump seat member being movable from a producing to a shut-in position;

means forming a spent power fluid flow passageway through said main body and in flow communication with the second zone, means forming a spent power fluid passageway through said pump seat member which is aligned with said passageway through said main body when the standing valve is in the producing conguration and which is misaligned therewith when the standing valve is in the shut-in configuration;

a bottom plug having a seat, a spent power fiuid outlet, and a produced fluid inlet, said bottom plug adapted to be received by said pump seat member to thereby urge said pump seat member into the production configuration to enable production fluid to flow to said produced fluid inlet of said pump while spent power uid ows from the spent power uid outlet to the second zone.

13. The apparatus defined in claim 9, and further including a standing valve, said standing valve including a main body member and a pump seat member, said pump seat member having means forming a seat which cooperates with said production fluid and said spent power uid passageways; said pump seat member having a portion thereof slidably received by said main body member with `said pump seat member being movable from a producing to a shut-in configuration;

means forming a spent power fluid flow passageway through said main body and in flow communication with the second zone, means forming a spent power fluid passageway through said pump seat member which is aligned with said passageway through said main body when the standing valve is in the producing configuration and which is misaligned therewith when the standing valve is in the shut-in configuration;

the lower end of the pump adapted to be received by said pump seat member to thereby urge said pump seat member into the production configuration to enable production fluid to flow to the pump while spent power fluid ows to the second zone.

References Cited UNITED STATES PATENTS 2,551,434 5/1951 Gray et al. 166-305 2,748,712 6/ 1956 Sargent 103-48 2,800,859 7/ 1957 Chenault 103-46 2,821,141 1/1958 Sargent 103-46 2,933,071 4/ 1960 Sargent et al 91-222 3,199,592 8/1965 Jacob 166-305 3,414,057 12/ 1968 Harbison 166-105 JAMES A. LEPPINK, Primary Examiner I. A. CALVERT, Assistant Examiner U.S. Cl. X.R. 

